N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) was investigated as an efficient and magnetically recoverable catalyst for the one-pot synthesis of substituted coumarins from the reaction of coumarin with variety aromatic aldehydes in high to excellent yield at room temperature under solvent-free conditions. The magnetic nanocatalyst can be readily recovered easily by applying an external magnet device and reused for at least 10 reaction runs without considerable loss of reactivity. The advantages of this protocol are the use of a commercially available, eco-friendly, cheap, the mild reaction conditions, operational simplicity, practicability, short reaction times, and good to high yields